public class Solution4 {
    public int[] productExceptSelf(int[] nums) {
        int n = nums.length;
        int[] f = new int[n];
        int[] g = new int[n];
        int[] ret = new int[n];

        //1. 处理前缀积以及后缀积
        f[0] = 1;
        g[n - 1] = 1;
        for(int i = 1; i < n; i++) {
            f[i] = f[i-1] * nums[i-1];
        }
        for(int i = n - 2; i >= 0; i--) {
            g[i] = g[i+1] * nums[i+1];
        }

        //2. 使用
        for(int i = 0; i < n; i++) {
            ret[i] = f[i] * g[i];
        }
        return ret;
    }
}
